Soist corpobatioit



j are rates WHITNEY B. JONES, CF NEWARK, NEW JERSEY, ASSIGNOE 'I'OBUTTERWORTH-JlID- SON CORPORATION, OF NEW YORK, N. Y A CORPORATION OFNEW YORK.

rnocass or MAKING NIrnoDIAzo COMPOUNDS.

No Drawing.

To all whom it may concern:

a citizen of the United States, residin at Newark, in the county ofEssex and Sitate of New Jersey, have invented certain new and usefulImprovements in Processes of Making Nitrodiazo Compounds, of which thefollowing is a specification.

It is known that nitro-diazo compounds capable, by coupling withbeta-naphthol, of yielding nitro-azo dyestuffs, may be prepared bysubjecting l-diaZO-QoXy-naphtli'alene-4-sulf0nic acid to nitration, asde-" scribed for example in U. S. Patent 790,363, patented May 23,1905,, to Hagenbach. In the practice of that process, however, theyields are relatively .small, and moreover difficulties are encounteredin the practical performance of the operation.

I have discovered that a much smoother operation, attended by superioryields, is.

attained if instead of the free acid, the corresponding metal salts aresubjected to the nitrating operation. For this purpose I prefer to usethe zinc salt, which maybe represented as follows:

=N N=N- Specification of Letters Patent. Patented 001:. 25, 1921.

Application filed March a, .1920. Serial No. 363,759. a i

improved yields, the use of the metallic salts Be it known that I,WHITNEY B. Jones,

as described herein offers the advantage that the final filtration isrendered commercially practicable.

A preferred example in accordance with my invention is as follows-:v i

562 pounds of the zinc salt of 1-diazo-2- oxy-naphthalenei-sulfonic acidin dried to 1687 pounds of monohydrate sulfuric acid, keeping thetemperature below 5 C."

When solution is complete 679 pounds of mixed acid, composed of 30%nitric and- 68% sulfuric acids, .are slowly run in, keepmass is stirredfor several hours after all of the'acid has been added, and is then runslowly into sufiicient ice to produce a final dilution of about 30%H',SO,. The ice cold mass is then filtered, and the resulting paste ofnitro compound is used direct in the manufacture of the dyestuif, forexample by couplin with beta-naphthol in the known manner.

. finely powdered condition, are added slowly My invention is of coursenot limited to the details of procedure and :manipulation as describedin the above specific example.

I claim: 1. Process of .making a nitro-diazo com pound, comprisingnitrating a metallic saltof l-diazo-2-oXy-napthalenel-sulfonic acid. '2;Process of making a nitro-diazo compound, comprising nitrating a zincsalt of 1-diazo-2-oXy-naphthalenel-sulfonic acid.

ture.

WHITNEY B. JONES.

In testimony whereof I affix my signs--

